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ETAP Workshop Notes © 1996-2010 ETAP/Operation Technology, Inc.
Load Flow Analysis
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 2
System ConceptsSystem Concepts
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 3
jQP
IV
SS
IVS
LL
LN
*
13
*1
3
3
Lagging Power Factor Leading Power Factor
Inductive loads have lagging Power Factors. Capacitive loads have leading Power Factors.
Current and Voltage
Power in Balanced 3-Phase Systems
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 4
Leading Power Factor
Lagging Power Factor
ETAP displays lagging Power Factors as positive and leading Power Factors as negative. The Power Factor is displayed in percent.
jQ P
Leading & Lagging Power Factors
P - jQ P + jQ
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 5
B
2B
B
B
BB
MVA
)kV(Z
kV3
kVAI
B
actualpu
B
actualpu
Z
ZZ
I
II
B
actualpu
B
actualpu
S
SS
V
VV
B
2B
B
B
BB
S
VZ
V3
SI
ZI3V
VI3S If you have two bases:
Then you may calculate the other two by using the relationships enclosed in brackets. The different bases are:
•IB (Base Current)
•ZB (Base Impedance)
•VB (Base Voltage)
•SB (Base Power)
ETAP selects for LF:
•100 MVA for SB which is fixed for the entire system.
•The kV rating of reference point is used along with the transformer turn ratios are applied to determine the base voltage for different parts of the system.
3-Phase Per Unit System
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 6
Example 1: The diagram shows a simple radial system. ETAP converts the branch impedance values to the correct base for Load Flow calculations. The LF reports show the branch impedance values in percent. The transformer turn ratio (N1/N2) is 3.31 and the X/R = 12.14
2B
1B kV
2N
1NkV
Transformer Turn Ratio: The transformer turn ratio is used by ETAP to determine the base voltage for different parts of the system. Different turn ratios are applied starting from the utility kV rating.
To determine base voltage use:
2
pu
pu
RX
1
RX
ZX
Transformer T7: The following equations are used to find the impedance of transformer T7 in 100 MVA base.
RX
xR pu
pu
1BkV
2BkV
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 7
Impedance Z1: The base voltage is determined by using the transformer turn ratio. The base impedance for Z1 is determined using the base voltage at Bus5 and the MVA base.
06478.0)14.12(1
)14.12(065.0X
2pu
005336.014.12
06478.0R pu
The transformer impedance must be converted to 100 MVA base and therefore the following relation must be used, where “n” stands for new and “o” stands for old.
)3538.1j1115.0(5
100
5.13
8.13)06478.0j1033.5(
S
S
V
VZZ
23
oB
nB
2
nB
oBo
punpu
38.135j15.11Z100Z% pu
0695.431.3
5.13
2N1N
kVV utility
B
165608.0100
)0695.4(
MVA
VZ
22B
B
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 8
8.603j38.60Z100Z% pu
)0382.6j6038.0(1656.0
)1j1.0(
Z
ZZ
B
actualpu
The per-unit value of the impedance may be determined as soon as the base impedance is known. The per-unit value is multiplied by one hundred to obtain the percent impedance. This value will be the value displayed on the LF report.
The LF report generated by ETAP displays the following percent impedance values in 100 MVA base
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 9
Load Flow AnalysisLoad Flow Analysis
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 10
1. Accelerated Gauss-Seidel Method
• Low Requirements on initial values, but slow in speed.
2. Newton-Raphson Method
• Fast in speed, but high requirement on initial values.
• First order derivative is used to speed up calculation.
3. Fast-Decoupled Method
• Two sets of iteration equations: real power – voltage angle, reactive power – voltage magnitude.
• Fast in speed, but low in solution precision.
• Better for radial systems and systems with long lines.
Load Flow Calculation Methods
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 11
kV
kVAFLA
kV
kVAFLA
EffPF
HP
EffPF
kWkVA
Rated
Rated
RatedRated
1
33
7457.0
Where PF and Efficiency are taken at 100 % loading conditions
kV
kVA1000I
)kV3(
kVA1000I
kVA
kWPF
)kVar()kW(kVA
1
3
22
Load Nameplate Data
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 12
TYPE OF LOADS:TYPE OF LOAD PHASOR PHASE
ANGLE
POWER ABSORBED BY THE LOAD
P Q
V
I
R VI Ф = 0° P > 0 Q = 0
V
I
L
V
I
Ф Ф = +90° P = 0 Q > 0
V
IC
V
I
Ф Ф = - 90° P = 0 Q < 0
R
L
R L
I
V
V
ΦV
I 0°<Φ<+90° P > 0 Q > 0
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 13
TYPE OF LOADS:TYPE OF LOAD PHASOR PHASE
ANGLE
POWER ABSORBED BY THE LOAD
P Q
-90°<Φ<0° P > 0 Q < 0
LI
V
-90°<=Φ<=+9
0°
P = 0 Q = 0
R
C
RC
V
V
I
IVΦ
C
Ic IL
Tuned to
Resonance
IL = Ic
PL = Pc
Energy travels
Back & forth
Between C&L
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 14
Constant Power Loads
• In Load Flow calculations induction, synchronous and lump loads are treated as constant power loads.
• The power output remains constant even if the input voltage changes (constant kVA).
• The lump load power output behaves like a constant power load for the specified % motor load.
• In Load Flow calculations Static Loads, Lump Loads (% static), Capacitors and Harmonic Filters and Motor Operated Valves are treated as Constant Impedance Loads.
• The Input Power increases proportionally to the square of the Input Voltage.
• In Load Flow Harmonic Filters may be used as capacitive loads for Power Factor Correction.
• MOVs are modeled as constant impedance loads because of their operating characteristics.
Constant Impedance Loads
© 1996-2008 Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 15
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 16
• The current remains constant even if the voltage changes.
• DC Constant current loads are used to test Battery discharge capacity.
• AC constant current loads may be used to test UPS systems performance.
• DC Constant Current Loads may be defined in ETAP by defining Load Duty Cycles used for Battery Sizing & Discharge purposes.
Constant Current Loads
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 17
Constant Current Loads
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 18
Load Type Summary
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 19
Exponential Load
Polynomial Load
Comprehensive Load
Generic Loads
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 20
Feedback Voltage •AVR: Automatic Voltage Regulation•Fixed: Fixed Excitation (no AVR action)
Generator Operation Modes
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 21
Governor Operating Modes
• Isochronous: This governor setting allows the generator’s power output to be adjusted based on the system demand.
• Droop: This governor setting allows the generator to be Base Loaded, meaning that the MW output is fixed.
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 22
Isochronous Mode
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 23
Droop Mode
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 24
Swing Mode•Governor is operating in Isochronous mode•Automatic Voltage Regulator
Voltage Control•Governor is operating in Droop Mode•Automatic Voltage Regulator
Mvar Control•Governor is operating in Droop Mode•Fixed Field Excitation (no AVR action)
PF Control•Governor is operating in Droop Mode•AVR Adjusts to Power Factor Setting
In ETAP Generators and Power Grids have four operating modes that are used in Load Flow calculations.
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 25
Generator Capability Curve
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 26
Generator Capability Curve
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 27
Generator Capability Curve
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 28
Field Winding Heating Limit
Armature Winding Heating Limit
Machine Rating (Power Factor Point)
Steady State Stability Curve
Maximum & Minimum Reactive Power
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 29
Field Winding Heating Limit Machine Rating
(Power Factor Point)
Steady State Stability Curve
Generator Capability Curve
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 30
Load Flow Loading Page
Generator/Power Grid Rating Page
10 Different Generation Categories for Every Generator or Power Grid in the System
Generation Categories
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 31
X
V)*COS(
X
*VVQ
)(*SINX
*VVP
X
V)(*COS
X
*VVj)(*SIN
X
*VV
jQPI*VS
22
2121
2121
22
2121
2121
222
111
VV
VV
Power Flow
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 32
Example: Two voltage sources designated as V1 and V2 are connected as shown. If V1= 100 /0° , V2 = 100 /30° and X = 0 +j5 determine the power flow in the system.
I
var536535.10X|I|
268j1000)68.2j10)(50j6.86(IV
268j1000)68.2j10(100IV
68.2j10I
5j
)50j6.86(0j100
X
VVI
22
*2
*1
21
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 33
2
1
0
1
Real Power FlowReactive Power Flow
Power Flow1
2
V E( )
Xsin
V E( )
Xcos
V2
X
0
The following graph shows the power flow from Machine M2. This machine behaves as a generator supplying real power and absorbing reactive power from machine M1.
S
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 34
ETAP displays bus voltage values in two ways
•kV value
•Percent of Nominal Bus kV
%83.97100%
5.13
min
alNo
Calculated
Calculated
kV
kVV
kV 8.13min alNokV
%85.96100%
03.4
min
alNo
Calculated
Calculated
kV
kVV
kV 16.4min alNokV
For Bus4:
For Bus5:
Bus Voltage
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 35
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 36
Lump Load Negative Loading
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 37
Exercise Time
• Open LF-Example-A1
• Follow instructions in LF-Example-A1.PDF
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 38
Load Flow Adjustments• Transformer Impedance
– Adjust transformer impedance based on possible length variation tolerance
• Reactor Impedance– Adjust reactor impedance based on specified tolerance
• Overload Heater– Adjust Overload Heater resistance based on specified tolerance
• Transmission Line Length– Adjust Transmission Line Impedance based on possible length
variation tolerance
• Cable Length– Adjust Cable Impedance based on possible length variation tolerance
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 39
Adjustments applied
•Individual
•Global
Temperature Correction
• Cable Resistance
• Transmission LineResistance
Load Flow Study Case Adjustment Page
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 40
Allowable Voltage DropNEC and ANSI C84.1
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 41
Load Flow Alerts
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 42
Bus Alerts Monitor Continuous Amps
Cable Monitor Continuous Amps
Reactor Monitor Continuous Amps
Line Monitor Line Ampacity
Transformer Monitor Maximum MVA Output
UPS/Panel Monitor Panel Continuous Amps
Generator Monitor Generator Rated MW
Equipment Overload Alerts
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 43
Protective Devices Monitored parameters % Condition reported
Low Voltage Circuit Breaker Continuous rated Current OverLoad
High Voltage Circuit Breaker Continuous rated Current OverLoad
Fuses Rated Current OverLoad
Contactors Continuous rated Current OverLoad
SPDT / SPST switches Continuous rated Current OverLoad
Protective Device Alerts
If the Auto Display feature is active, the Alert View Window will appear as soon as the Load Flow calculation has finished.
© 1996-2009 Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 44
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 45
Exercise Time
• Open LF-Example-B1
• Follow instructions in LF-Example-B1.PDF
Load Flow Example B1 Part 1
© 1996-2009 Operation Technology, Inc. - Workshop Notes: Load Flow AnalysisSlide 46
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 47
Load Flow Example B1 Part 2
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 48
Voltage Control
• Under/Over Voltage Conditions must be fixed for proper equipment operation and insulation ratings be met.
• Methods of Improving Voltage Conditions:
– Transformer Replacement
– Capacitor Addition
– Transformer Tap Adjustment
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 49
Under-Voltage Example
• Create Under Voltage Condition
– Change Syn2 Quantity to 6. (Info Page, Quantity Field)
– Run LF
– Bus8 Turns Magenta (Under Voltage Condition)
• Method 1 - Change Xfmr
– Change T4 from 3 MVA to 8 MVA, will notice slight improvement on the Bus8 kV
– Too Expensive and time consuming
• Method 2 - Shunt Capacitor
– Add Shunt Capacitor to Bus8
– 300 kvar 3 Banks
– Voltage is improved
• Method 3 - Change Tap
– Place LTC on Primary of T6
– Select Bus8 for Control Bus
– Select Update LTC in the Study Case
– Run LF
– Bus Voltage Comes within specified limits
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 50
Advanced LF TopicsAdvanced LF Topics
Voltage Control
Mvar Control
Load Flow Convergence
Load Flow vs. Optimal Power Flow
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 51
Mvar Control
• Vars from Utility
– Add Switch to CAP1
– Open Switch
– Run LF
• Method 1 – Generator
– Change Generator from Voltage Control to Mvar Control
– Set Mvar Design Setting to 5 Mvars
• Method 2 – Add Capacitor
– Close Switch
– Run Load Flow
– Var Contribution from the Utility reduces
• Method 3 – Xfmr MVA
– Change T1 Mva to 40 MVA
– Will notice decrease in the contribution from the Utility
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 52
Advanced LF TopicsAdvanced LF Topics
Voltage Control
Mvar Control
Load Flow Convergence
Load Flow vs. Optimal Power Flow
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 53
Load Flow Convergence
• Negative Impedance
• Zero or Very Small Impedance
• Widely Different Branch Impedance Values
• Long Radial System Configurations
• Bad Bus Voltage Initial Values
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 54
Exercise Time
• Open LF-Example-A2
• Follow instructions in LF-Example-A2.PDF
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 55
Advanced LF TopicsAdvanced LF Topics
Voltage Control
Mvar Control
Load Flow Convergence
Load Flow vs. Optimal Power Flow
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 56
Review of Load Flow Solution
• Given generation, loading and control settings (Mwgen, Vgen, LTC, Capacitor Bank, …)
• Solve bus voltages and branch flows
• Check over/under voltage, device overloading conditions
• Reset controls and run Load Flow again
• Iterative process
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 57
Optimal Power Flow Approach
• Given control setting ranges
• Specify bus voltage and branch loading constraints
• Select optimization objectives (Min. P Losses, Min. Q Losses, …)
• Solve bus voltages, branch flows and control settings
• Direct solution
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 58
Control Variables
• Load Tap Changer (LTC) Settings• Generator AVR Settings• Generator MW Generation• Series or Shunt VAR Compensator Settings• Phase Shift Transformer Tap Positions• Switched Capacitor Settings• Load Shedding• DC Line Flow• …
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 59
Objective Functions
• Minimize Real Power Losses
- To minimize real power losses in the system
• Minimize Reactive Power Losses
- To minimize reactive power losses in the system
• Minimize Swing Bus Power
- To minimize real power generation at the swing bus(s)
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 60
Objective Functions
• Minimize Shunt var Devices
- To minimize var generation from available shunt var control devices
• Minimize Fuel Cost
- To minimize total generation fuel cost
• Minimize Series Compensation
- To minimize var generation from available series var control devices
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 61
Objective Functions
• Minimize Load Shedding
- To minimize load to be shed from the available bus load shed schedule
• Minimize Control Movement
- To minimize total number of controls
• Minimize Control Adjustment
- To minimize overall adjustment from all controls
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 62
Objective Functions
• Maximize Voltage Security Index
Where,
AllBuses
i
n
i
avgii
dV
VV2
,IndexSecurity Voltage
2min,max,
,ii
avgi
VVV
2min,max, ii
i
VVdV
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 63
• Maximize Line Flow Security Index
Where, is the line rating
• Flat Voltage Profile- Voltage Magnitude difference between all
buses is minimum
Objective Functions
sAllBranche
i
n
i
i
S
S2
IndexSecurity Flow Line
iSd
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 64
Other Constraints
• Bus Voltage Constraints
• Branch Flow Constraints
• Interface Flow Constraints
• …
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 65
Exercise Time
• Open LF-Example-A3
• Follow instructions in LF-Example-A3.PDF
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 66
Comparison of LF and OPF
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 67
Panel SystemsPanel Systems
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 68
Panel Boards• They are a collection of branch circuits
feeding system loads
• Panel System is used for representing power and lighting panels in electrical systems
Click to drop once on OLVDouble-Click to drop multiple panels
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 69
A panel branch circuit load can be modeled as an internal or external load
Advantages:1. Easier Data Entry2. Concise System Representation
Representation
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 70
Pin 0 is the top pin of the panel ETAP allows up to 24 external load connections
Pin Assignment
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 71
Assumptions
• Vrated (internal load) = Vrated (Panel Voltage)
• Note that if a 1-Phase load is connected to a 3-Phase panel circuit, the rated voltage of the panel circuit is (1/√3) times the rated panel voltage
• The voltage of L1 or L2 phase in a 1-Phase 3-Wire panel is (1/2) times the rated voltage of the panel
• There are no losses in the feeders connecting a load to the panel
• Static loads are calculated based on their rated voltage
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 72
Line-Line Connections
Load Connected Between Two Phases of a3-Phase System
A
B
C
Load
IBCIC = -IBC
A
B
C
LoadB
IB = IBC
Angle by which load current IBC lags the load voltage = θ Therefore, for load connected between phases B and C: SBC = VBC.IBC
PBC = VBC.IBC.cos θ
QBC = VBC.IBC.sin θ
For load connected to phase B SB = VB.IBPB = VB.IB.cos (θ - 30)QB = VB.IB.sin (θ - 30) And, for load connected to phase C SC = VC.ICPC = VC.IC.cos (θ + 30)QC = VC.IC.sin (θ + 30)
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 73
3-Phase 4-Wire Panel3-Phase 3-Wire Panel1-Phase 3-Wire Panel1-Phase 2-Wire Panel
NEC SelectionA, B, C from top to bottom or left to right from the front of the panel
Phase B shall be the highest voltage (LG) on a 3-phase, 4-wire delta connected system (midpoint grounded)
Info Page
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 74
Intelligent kV CalculationIf a 1-Phase panel is connected to a 3-Phase bus having a nominal voltage equal to 0.48 kV, the default rated kV of the panel is set to (0.48/1.732 =) 0.277 kV
For IEC, Enclosure Type is Ingress Protection (IPxy), where IP00 means no protection or shielding on the panel
Select ANSI or IEC Breakers or Fuses from Main Device Library
Rating Page
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 75
Schedule Page
Circuit Numbers with Column Layout
Circuit Numbers with
Standard Layout
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 76
Description TabFirst 14 load items in the list are based on NEC 1999Last 10 load types in the Panel Code Factor Table are user-definedLoad Type is used to determine the Code Factors used in calculating the total panel loadExternal loads are classified as motor load or static load according to the element typeFor External links the load status is determined from the connected load’s demand factor status
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 77
Rating Tab
Enter per phase VA, W, or Amperes for this load.
For example, if total Watts for a 3-phase load are 1200, enter W as 400 (=1200/3)
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 78
Loading Tab
For internal loads, enter the % loading for the selected loading category
For both internal and external loads, Amp values are calculated based on terminal bus nominal kV
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 79
Protective Device Tab
Library Quick Pick - LV Circuit Breaker (Molded Case, with Thermal Magnetic Trip Device) or
Library Quick Pick – Fuse will appear depending on the Type of protective device selected.
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 80
Feeder Tab
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 81
Action Buttons
Copy the content of the selected row to clipboard. Circuit number, Phase, Pole, Load Name, Link and State are not copied.
Paste the entire content (of the copied row) in the selected row. This will work when the Link Type is other than space or unusable, and only for fields which are not blocked.
Blank out the contents of the entire selected row.
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 82
Summary Page
Continuous Load – Per Phase and Total
Non-Continuous Load – Per Phase and Total
Connected Load – Per Phase and Total (Continuous + Non-Continuous Load)
Code Demand – Per Phase and Total
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 83
Output Report
© 1996-2010 ETAP/Operation Technology, Inc. – Workshop Notes: Load Flow Analysis Slide 84
Panel Code Factors
Code demand load depends on Panel Code Factors
The first fourteen have fixed formats per NEC 1999
Code demand load calculation for internal loads are done for each types of load separately and then summed up